Difference between rendering in Library and Develop module

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  • Updated 2 years ago
There's a difference between the rendering in the Develop and Library module. It's especially visible in the example below, where the arrow points to the upper left part of an area that almost looks posterized in some sort of magenta.

When I export the file as a jpg, the exported file looks fine, whether exported in sRGB or AdobeRGB color space.

To me this looks like an error in image rendering in the Library module. Fortunately not in the Develop module, where it would be really harmful.
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Ad Dieleman

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Posted 2 years ago

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Bhargav, Official Rep

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Hi Ad Dieleman,

Which version of Lightroom are you using?

Do you see the issue with every image you have?

Is it same with both GPU On and Off?
If not, can you share the results with GPU On and Off.

P.S : To Turn off GPU. Go to Lightroom -> Preferences -> Performance and uncheck "Use Graphics Processor".

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Dave Pearce

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I believe its always been the case that previews in the two modules are different. Im not sure if things should have changed recently though.
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Ad Dieleman

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I'm using Lightroom Classic 7.0 Release Camera Raw 10.0, iMac with macOS Sierra 10.12.6, display profile comes from calibration with Datacolor Spyder5Elite.

There are noticeable differences in other pictures too, more subtle than in the one shown but certainly there.

I had GPU turned on, turning it off doesn't make a difference for the posterization effect in the Library module. There is a difference in shadow rendering in the Develop module between GPU on and off, as others have already noted.
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Develop= Prophoto RGB colorspace. Library= Adobe 98 RGB colorspace
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Simon Chen, Principal Computer Scientist

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Hi Ad,

Looking at your example. I think I know the issue. If you zoom to 1:1 in the library loupe, the 1:1 preview would show no posterization even after you zooming out.

The posterization render could happen if Lightroom renders the preview based on Smart Preview or preview negatives stored in the Camera Raw Cache (called preview quality negatives), when Lr finds out that the image dimension of the preview quality negative is sufficient to render the Standard Preview for the library loupe display. In this case, Lr will not dig deeper into loading the full sized negative to generate the Standard Previews for performance reasons. For export and develop renders, Lr always renders from the full resolution negative so you don't see the posterization.

The posterization would more likely be visible if you apply some extreme valued adjustments to preview quality negatives. Because the preview quality negatives are 8-bit lossy compressed. When they undergo extreme valued adjustments. The artifacts could appear.

If you use the Color Range Mask in the Lr Classic CC, similar artifacts could also appear on renders generated from the preview quality negatives. We intends to fix this in the 7.1 release.
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Ad Dieleman

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Hi Simon,

You're right, after zooming in to 1:1 the posterization disappears and stays away when zooming out. Fyi, no extreme adjustments in this picture, I didn't touch it after the upgrade to the 7.0 Release.

Thanks for your answer, I know now what to do.
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Jerry Syder

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Ad, from my experience, this can happen too, if the image was shot with high a ISO or if the shadows/ exposure needed to be bumped up i.e. in a slightly underexposed image. I think anything other than the full resolution negative it's risky(for LR) as there seems to be too many variables that can cause the posterization you're seeing but as Simon says, it's being worked on :-)